A duplexer is a critical component in the functioning of wireless transceivers, such as mobile phones, wireless network adapters, and PDAs. It allows simultaneous transmission and reception of signals from a single antenna. It provides isolation between transmitter and receiver. Generally speaking, the duplexers currently used in transceivers are passive filters and hence have insertion loss across the device. Furthermore, they are not tunable, or if they are tunable, they are not tunable electronically, and they do not provide amplification of transmitted and received signals.